/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { posix } from 'path-browserify';

import { CharCode } from './char-code';
import type { URI } from './uri';

const posixPath = posix;
const slash = '/';

export namespace Utils {
  /**
   * Joins one or more input paths to the path of URI.
   * '/' is used as the directory separation character.
   *
   * The resolved path will be normalized. That means:
   *  - all '..' and '.' segments are resolved.
   *  - multiple, sequential occurences of '/' are replaced by a single instance of '/'.
   *  - trailing separators are preserved.
   *
   * @param uri The input URI.
   * @param paths The paths to be joined with the path of URI.
   * @returns A URI with the joined path. All other properties of the URI (scheme, authority, query, fragments, ...) will be taken from the input URI.
   */
  export function joinPath(uri: URI, ...paths: string[]): URI {
    return uri.with({ path: posixPath.join(uri.path, ...paths) });
  }

  /**
   * Resolves one or more paths against the path of a URI.
   * '/' is used as the directory separation character.
   *
   * The resolved path will be normalized. That means:
   *  - all '..' and '.' segments are resolved.
   *  - multiple, sequential occurences of '/' are replaced by a single instance of '/'.
   *  - trailing separators are removed.
   *
   * @param uri The input URI.
   * @param paths The paths to resolve against the path of URI.
   * @returns A URI with the resolved path. All other properties of the URI (scheme, authority, query, fragments, ...) will be taken from the input URI.
   */
  export function resolvePath(uri: URI, ...paths: string[]): URI {
    let path = uri.path;
    let slashAdded = false;
    if (path[0] !== slash) {
      path = slash + path; // make the path abstract: for posixPath.resolve the first segments has to be absolute or cwd is used.
      slashAdded = true;
    }
    let resolvedPath = posixPath.resolve(path, ...paths);
    if (slashAdded && resolvedPath[0] === slash && !uri.authority) {
      resolvedPath = resolvedPath.substring(1);
    }
    return uri.with({ path: resolvedPath });
  }

  /**
   * Returns a URI where the path is the directory name of the input uri, similar to the Unix dirname command.
   * In the path, '/' is recognized as the directory separation character. Trailing directory separators are ignored.
   * The orignal URI is returned if the URIs path is empty or does not contain any path segments.
   *
   * @param uri The input URI.
   * @return The last segment of the URIs path.
   */
  export function dirname(uri: URI): URI {
    if (uri.path.length === 0 || uri.path === slash) {
      return uri;
    }
    let path = posixPath.dirname(uri.path);
    if (path.length === 1 && path.charCodeAt(0) === CharCode.Period) {
      path = '';
    }
    return uri.with({ path });
  }

  /**
   * Returns the last segment of the path of a URI, similar to the Unix basename command.
   * In the path, '/' is recognized as the directory separation character. Trailing directory separators are ignored.
   * The empty string is returned if the URIs path is empty or does not contain any path segments.
   *
   * @param uri The input URI.
   * @return The base name of the URIs path.
   */
  export function basename(uri: URI): string {
    return posixPath.basename(uri.path);
  }

  /**
   * Returns the extension name of the path of a URI, similar to the Unix extname command.
   * In the path, '/' is recognized as the directory separation character. Trailing directory separators are ignored.
   * The empty string is returned if the URIs path is empty or does not contain any path segments.
   *
   * @param uri The input URI.
   * @return The extension name of the URIs path.
   */
  export function extname(uri: URI): string {
    return posixPath.extname(uri.path);
  }
}